Recently more and more surveillance systems are popularly being used for protecting people's wealth and security. A panoramic camera was invented so that a surveillance system could monitor environments without any dead angles. The panoramic camera can be embodied by a multi-lenses assembly, or by a single fisheye lens. The panoramic camera supports the wide-angle photographing without any dead angles.
However, the panoramic camera cannot support an optical zoom, so an observer can not zoom in on an object under observation in a panoramic image captured by the panoramic camera. Even though the panoramic camera supports a digital zoom to enlarge its panoramic image for observing an object under observation in the enlarged panoramic image, the panoramic camera can not fulfill the actual requirements yet. Because this digital zoom is accomplished by cropping an image down to a centered area with the same aspect ratio as the original, and usually also interpolating the result back up to the pixel dimensions of the original, the resolution of the enlarged panoramic image will greatly reduce. If there is an accident that happened far away from the panoramic camera, it will be difficult for an observer to clearly observe the object under observation in the obtained panoramic image.
As compared with the panoramic camera, a pan-tilt-zoom (PTZ) camera can support the optical zoom so that it can zoom in to change its field of view (FOV), so as to zoom in on a remote object under observation. The FOV of the PTZ camera is smaller than the FOV of the panoramic camera. Thus, the PTZ camera is applied to cooperate with the panoramic camera in order to capture the details of the same view.
The angles of view of cameras disposed in different locations may be not the same, so when the PTZ camera is driven according to what the panoramic camera focuses on in the same environment, the FOV of the panoramic camera and the FOV of the PTZ camera will have differences therebetween. Therefore, the panoramic camera and the PTZ camera in such a surveillance system have to be disposed as close to each other as possible.